The present invention relates to the field of practice ammunition and, more specifically, to an ammunition projectile that can mark its point of impact both by day and by night.
Military forces currently use a wide array of technologies to detect and identify targets and adjust fire. Traditionally, military forces have used pyrotechnic devices in training ammunition allowing gunners to mark targets, but these pyrotechnic devices naturally result in unexploded ordnance (UXO) which is expensive to clean up. Pyrotechnic devices can also start range fires that destroy the environment and frequently cause the cessation of training exercises. The U.S. Army's current 40 mm M918 cartridge is an example of commonly used pyrotechnic training ammunition.
To prevent the generation of UXO and range fires during training, it is useful to develop inert practice ammunition projectiles which do not employ energetic pyrotechnics.
Nevertheless, good military training devices should simulate the effects of live fire high-explosive detonations. High explosive detonations in combat generate visual and near infra-red light and heat, forming a multi-spectral signature. High explosive detonations also produce smoke plumes. The light and heat resulting from high explosive detonations can be detected by an array of fire control devices used by the military. Smoke plumes are visible to the naked eye.
Military forces frequently use target locating devices with visual cameras and cameras that operate in the near and/or far IR spectrum. Accordingly it is desired that practice ammunition simulate the effects seen in combat and that practice ammunition generate multi-spectral marking signatures, upon impact, that can be viewed by these cameras.
Chemi-luminescent technology, such as that taught in the Haeselich U.S. Pat. No. 6,619,211, has been used to transmit visible energy to mark the trace and impact of practice ammunition. There are, however, certain drawbacks to this technology as currently practiced: (1) Chemi-luminescent materials do not work well at low temperatures, and (2) currently available chemi-luminescent materials do not generate enough heat to provide a good signature for thermal weapon sensors.
In the past, pyrotechnic devices have generally produced a smoke and heat plume that resulted from combustion of the pyrotechnic compounds. Also, ordnance designers have packaged visible marking materials, such as one simple buoyant marking material, inside of frangible ogives, to create visible marking plumes. This technology has been used, for example, in the U.S. Army's vintage M781 design. Rheinmetall GmbH & Co. (Germany) has developed ammunition like the MK281 MOD 0 which was introduced to United States forces in 2003. These M781 and MK281 designs have packaged a single buoyant marking material that generates a simple visual plume on impact.
It is important to recognize that military gunners often fire their weapons at long range in military training areas that include grass, vegetation and low lying trees. Hence, while there is some value to package and fire materials that directly mark a target (as is discussed, for example, in the Manole U.S. Pat. No. 7,055,438) the morphology and terrain on a military range frequently preclude gunners from having direct visibility of the actual impact point.